1. Field of the Invention
The present invention relates to an apparatus and method for interference-fitting (tightly fitting) an inner member with an annular outer member. The inner member has a flat portion substantially perpendicular to an axis of the inner member and a substantially cylindrical flange extending in the axial direction from the outermost end of the flat portion. This apparatus and method can be used in the fitting of a disk into a rim of a disk wheel of a vehicle.
2. Description of the Prior Art
A prior art fitting of a disk into a rim of a disk wheel will be explained referring to FIG. 3. In the prior art fitting, an inner member 31 of the disk is carried on a carrying member 32 such that inner member 31 is supported by carrying member 32 only at the radially inner portion of inner member 31. An outer member 33 of the rim to be interference-fitted with inner member 31 is held between upper and lower outer member supports, 34 and 35, respectively, and is moved relative to inner member 31 by lowering a slide 36 of a press apparatus. It should be noted that inner member 31 is not supported at its flange 31a extending from the radially outermost end of the flat portion of inner member 31 in the axial direction.
Because the disk has a plurality of fashion holes arranged around the axis of the disk, inner member 31 does not have a uniform rigidity in the circumferential direction of inner member 31. Further, because the flange of the disk has a plurality of recesses which recede in the axial direction of the disk from the free end of the flange and are formed spaced from each other in the circumferential direction of the flange, and because the surface of the free end of the flange is not always included in a single plane perpendicular to the axis of the disk, inner member 31 cannot be supported in the axial direction at its flange 31a. Furthermore, because the rim is formed by a rolling formation of a plate and the disk is formed by a press formation of a plate, inner member 31 and outer member 33 are not always formed to exactly circular contours.
Outer member 33 is interference-fitted to inner member 31, which is not supported at its outermost end during the fitting process, by adding an axial force which may be non-uniform in the circumferential direction. Therefore, inner member 31 will be inclined, receive the non-uniform force, and unwanted inclination will occur in the fitting with outer member 33. Further, the inclined fitting will cause a complicated torsional deformation in inner member 31 due to the circumferentially non-uniform rigidity of inner member 31. When such an inclination and a torsional deformation of inner member 31 exceed the allowable limits, the disk wheel has to be ejected from the wheel manufacture line as a defective one.
For the purpose of preventing inclination and torsional deformation of inner member 31 during the interference-fitting, it would be the best way to support inner member 31 at its outermost portion. However, as discussed previously, the prior art cannot support inner member 31 at its outermost portion.